WARRENTON, Georgia (CNN) -- The bodies of two toddlers reported missing Saturday were found Monday in a pond near their rural Georgia home, state investigators said.

The bodies of 2-year-old Nicole Payne and 3-year-old Jonah Payne were discovered in a sanitation pond a few hundred yards from their home about 12:15 p.m., said John Bankhead, a spokesman for the Georgia Bureau of Investigation.

"It appears that our worst fears have been realized," he said.

Investigators had searched the pond during the weekend but found nothing. However on Monday, one searcher noticed "kind of a bump in that green bacteria or algae on the surface of that sanitation pond," Bankhead said. That bump turned out to be Nicole's corpse.

Jonah's remains turned up a few feet away, Bankhead said. The children's father, Dennis Payne, identified the bodies in a photograph, he said.

The bodies were taken to a state crime lab in Augusta, about 40 miles east of Warrenton, where an autopsy will be performed, Bankhead said. There was no immediate indication of foul play, but investigators are continuing to look into circumstances surrounding their deaths, he said.

"We have surveyed the entire area to see if there might be any evidence to indicate that they maybe slipped in," he said.

Before the bodies were found, Bankhead said that while authorities "are trying to concentrate our efforts on finding the kids, there are other aspects of the investigation that we're pursuing that I can't get into at this point."

He said that authorities had interviewed several people and administered more than one polygraph examination.

"I can't talk specifically about polygraph examinations," he said. "I will say generally that a polygraph is a valuable tool in these type of investigations."

The children's parents, Lottie Kain and Dennis Payne, attended a Monday morning news conference but did not participate. Payne embraced the sobbing Kain.

Jay Jones, a friend of the parents, said that they were "understandably upset."

Warrenton Police Chief Jim McClain said Kain called 911 shortly before 6 p.m. Saturday and reported that the toddlers had disappeared from their home in Warrenton when she went to the bathroom for a few minutes.

Search teams -- both law enforcement and volunteer -- worked all night Saturday and most of Sunday before fatigue set in, and officials called a timeout. The search resumed Monday morning.

Georgia Bureau of Investigation officials told The Augusta Chronicle that they have not seen evidence to indicate anyone abducted the children. But Payne, Kain's fiance, told the paper he believed someone took them.